In order to protect plants already grown or seeds coming up, for instance in the months of spring, it is known to cover the plants with foils or sheets. By means of this foil- or sheet-like material which mostly is strip-like, the plants or the seeds are protected from weather influences, in particular precipitation and cold.
If the plants in the field are in close vicinity in continuous rows, these rows being in parallel to each other at a certain distance, it is known to spread the strip-like material over the individual rows in the direction of their extension, and to fix them by means of weighing them down at both sides of the rows. This weighing down is effected either by stones, wooden bars or the like laid down on the edge of the material, or else the two lateral edges of the material extending in the longitudinal direction are covered with soil by means of digging or ploughing up.
This known procedure has established itself due to the lacking of other measures or devices despite the disadvantages entailed. The disadvantages in the case of these known measures of fixing or fastening foil- or sheet-like material on the ground are, among others, the following:
In the case of these known measures it is necessary to spread the material in advance at least over a predetermined length over the plants or the like to be protected in order to subsequently press down the lateral edges by means of objects laid thereupon or by drawing a soil furrow at both sides. In the case of windy weather, however, the material may be blown up and reversed time and again, before it is possible to fasten the edges.
Keeping down the edges by means of objects such as for instance wooden bars, stones or the like, is a complicated, longwinded and strenuous task. In the case of major plantations, for instance so-called strawberry fields or plantations, the total length of the individual planting rows may easily amount to several kilometers. The sheet- or foil covers then will be correspondingly long, and correspondingly many wooden bars, stones or the like will have to be available.
If the edges of the foil- or sheet-like material are pressed down by means of drawing a soil furrow, the complicated laying down of objects for the sake of weighing down the material and the subsequent removal of these objects in the course of taking off the covering is indeed not necessary, but the drawing of a soil furrow requires a certain amount of space. In the case of parallel planting rows, the space between the individual planting rows even has to be large enough to be able to draw two soil furrows in order to press down the two edges of the respective covers between the individual planting rows. This reduces the usable area under cultivation in a disadvantageous way.
Furthermore, the ploughing at both sides of the covers produces a more or less high earthwork which may, in the case of a water-impermeable cover of plastic foil, prevent rain or dew water from running down from the foil laterally. Thus, water puddles may form on the foil cover, which might press down and damage the plants thereunder.